The present invention relates to a method of manufacturing a gas tank.
For example, in a fuel cell system to be installed in a vehicle such as an automobile, a high-pressure gas tank is used as a supply source of fuel gas.
In a manufacturing process of this type of gas tank, a fiber that is impregnated with thermosetting plastics is wound around a substantially ellipsoidal liner (inner container) and around part of mouthpieces provided at respective two ends of the liner to form a fiber reinforced plastics (FRP (Fiber Reinforced Plastics)) layer, and the fiber reinforced plastics layer is then thermally cured. As a method of carrying out this thermal curing, heating the fiber reinforced plastics layer through induction heating has been proposed (see Patent Document 1).
Patent Document 1: Patent Publication JP-A-06-335973
However, if induction heating mentioned above is used, the mouthpiece portions are not heated by induction depending on the material of the mouthpieces. Therefore, a difference in temperature between the mouthpieces and portions of the fiber reinforced plastics layer that are in contact with the respective mouthpieces becomes excessively large during thermal curing. Thus, a large amount of heat in those portions of the fiber reinforced plastics layer is conducted to the mouthpieces, and the heating efficiency of the fiber reinforced plastics layer decreases. Furthermore, the portions of the fiber reinforced plastics layer that are in contact with the respective mouthpieces become less likely to be heated, and thus the entire fiber reinforced plastics layer may not be cured uniformly, which may generate unevenness in the strength of the gas tank.